1. Field of the Invention
The invention relates to a magnetic heat exchange unit, and more particularly, the invention concerns a novel fluid pathway structure which is applied in a magnetic heat exchange unit.
2. Description of the Related Art
Magnetic refrigeration is considered as a highly efficient and environment-friendly cooling technology. Magnetic refrigeration technologies adapt magnetocaloric effect of magnetocaloric materials (MCM) to realize or utilize refrigeration cycles.
Specifically, magnetocaloric refrigeration is realized by the following steps: (1) a magnetic field is applied to magnetocaloric materials, and an increasing external magnetic flux causes the magnetocaloric materials to heat up; (2) while the magnetic field is held constantly, a coolant is provided to take away heat generated from the magnetocaloric materials; (3) once the magnetocaloric materials are sufficiently cooled down, the magnetic field is removed or decreased largely, and the coolant is stopped from being supplied thereto; and (4) due to its nature of having magnetocaloric effect, the magnetocaloric materials turn to cool down to a lower temperature. Then, a working fluid is provided to bring coldness from the magnetocaloric materials.
Japan patent publication No. 2009524796 discloses a magnetic heat exchange unit. The heat exchange unit has a case and a plurality of magnetocaloric materials disposed in the case. The magnetocaloric materials are connected in a baffle manner, and thus a plurality of fluid pathways are formed therebetween. While operating the magnetic heat exchange unit, a heat transfer medium flows through the fluid pathways to exchange heat generated from the magnetocaloric materials.
World patent publication No. 2009024412 utilizes a round shaped magnetocaloric bed as a magnetic heat exchange unit, wherein a plurality of fin shaped plates are disposed on the magnetocaloric bed, and fluid pathways are defined between each two neighboring fin shaped plates, respectively. A heat transfer medium is forced to flow through the fluid pathways so as to exchange with heat generated from the magnetocaloric bed.
In the described patents, however, temperature differences between the heat transfer media and the magnetocaloric materials are gradually decreased along the fluid pathways resulting in a decrease in heat exchange efficiency. Additionally, magnetocaloric materials are wasted because the magnetocaloric materials disposed in the fluid outlet can not perform a better refrigeration cycle. Such wasting profoundly increases cost and hinders economic considerations.